Eliminação do R-22, retrofit e novos fluidos refrigerantes com baixo GWP – estudo comparativo com os fluidos refrigerantes R-444B e R-454C

• Ano de defesa: 2024
• Autor(a) principal: Carlos Henrique Moreira Braga
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ENG - DEPARTAMENTO DE ENGENHARIA MECÂNICA; Programa de Pós-Graduação em Engenharia Mecanica; UFMG
• Palavras-chave em Português: Ar condicionado; Retrofit; Modelo; R-22; R-444B; R-454C; HFO; Sustentabilidade; Refrigeradores; Energia - Consumo; Refrigeração; Modelos matemáticos; Fluidos refrigerantes; Trocadores de calor; Aquecimento global
• Link de acesso: http://hdl.handle.net/1843/75913

Air conditioning systems have great relevance in the context of the planet's ecological issues and sustainability. It can be said that, directly or indirectly, they are present in the lives of more than seven billion people. When it comes to air conditioning systems, some solutions that have gained increasing prominence concern the retrofit of these systems, among which new refrigerant technologies stand out. The present work aims to evaluate the process of replacing the refrigerant fluid R-22 in air conditioning systems with refrigerant fluids R-444B and R-454C due to the large number of systems that still use it, especially in developing countries, such as Brazil. In order to allow an effective comparison between refrigerant fluids, a mathematical model was developed to measure the cooling capacity, electrical consumption and coefficient of performance of air conditioning systems using the fluids in an air conditioning system originally designed to operate with the R-22. The mathematical model of the heat exchangers was developed using the moving boundary technique and the compressor was modeled as recommended by the ISO9309 standard. The model was experimentally validated by comparing several results obtained in the laboratory using R-22. Considering all validated quantities, 95% of the results are within the error range of ±10%. There was an average reduction in cooling capacity of 6.3% for R-444B and 8.9% for R-454C when compared to R-22. Furthermore, there was an average increase in electrical consumption of 10.0% for R-444B and 3.7% for R-454C when compared to R-22. Consolidating these data, there was an average reduction in COP of 14.7% for R-444B and 12.1% for R-454C when compared to R-22. In line with the results available in the specialized literature, there was a drop in system performance when operating with new refrigerant fluids.